Nothing will happen to you. The belief in God is an option for me. We always refer to the Christian belief but there are so many religions out there and so many Gods. Depends on where you came from, where you're at, how you've been conditioned.
I believe in God, there is a God responsible for the creation of this amazing and magnificent universe. But that's it. I just don't believe in any religion and out of the goodness of my heart, I try to be good and not a parasite in my community and my country.
I'm not in any organized religion and I choose not to. I'm a Deist. You can not or can believe in God. A supreme being. It's actually optional. Do animals believe in God? A supreme being created those animals too.
That's just me. Science - Religion. They differ. You have the freedom to believe whatever it is you believe in.